Spinal fixation has become a common approach in treating spinal disorders, fractures, and for fusion of vertebrae, for example, in cases of trauma, tumors, and degenerative conditions. A common device used for spinal fixation is a bone fixation plate. A typical bone fixation plate includes a relatively flat, rectangular plate having a plurality of apertures therethrough. A corresponding plurality of fasteners, such as bone screws, are provided to secure the bone fixation plate to one or more bones, such as two adjacent spinal vertebrae.
A common problem associated with the use of such fixation plates, however, is the tendency of the bone screws to “back out” of the underlying bone under the stress of bodily movement. This problem occurs primarily due to the normal motion of the body, but may be particularly prevalent in areas of high stress, such as, for example, in the spine. Given the delicate nature of the spine, any post-operative fixation plate movement may not only frustrate the surgical goals, but may also raise patient safety concerns.
A number of various designs have been brought forth in attempts to lock the screws to the bone fixation plate, prevent screws from pulling away from the bone, or to prevent the screws from backing out or pulling away from the bone fixation plate. While there are many designs in this area, it is desirable to have improved locking devices and systems having locking features integrated with the bone plate, which have enhanced functionality and ease of use.